1. Field of the Invention
The present invention relates to a hinge apparatus and an image displaying apparatus, and more specifically to a hinge apparatus and an image displaying apparatus provided with a hinge structure for opening and closing an image displaying panel displaying an image.
2. Related Background of the Invention
An image displaying apparatus provided with a thin image displaying panel such as a liquid crystal display element is conventionally known. Specifically, as the image displaying apparatus, a video camera, a digital still camera, a mobile phone, a notebook computer, a portable DVD (Digital Versatile Disc) player or the like is known.
The image displaying apparatus is provided with an apparatus main body and an image displaying panel. Furthermore, some of these image displaying apparatuses each includes a hinge apparatus employed to couple the image displaying panel with the apparatus main body such that the image displaying panel can be opened or closed with respect to the apparatus main body. Normally, the hinge apparatus is constructed so as to keep a closed state in which the image displaying panel is in a close contact with the apparatus main body when the image displaying apparatus is not used, as well as so as to keep an opened state in which the image displaying panel stands about at 90° with respect to the apparatus main body when the image displaying apparatus is used.
In the case where the image displaying apparatus is a notebook computer or a portable DVD player, a hinge apparatus can be turned about one axis between the closed state and the opened state. In contrast, in the case where the image displaying apparatus is a video camera, a digital still camera or a mobile phone, the hinge apparatus can be turned about one axis between the closed state and the opened state, as well as can be turned about the other axis in the opened state. That is, the hinge apparatus is constructed such that the image displaying panel can be turned about a first axis and a second axis which intersect at right angles with each other.
In Japanese Patent Application Laid-Open No. 2001-272719, disclosed is a hinge apparatus provided with a substantially L-shaped hinge fixing member, a hinge rotating member, a pair of first rotary shaft members and a second rotary shaft member. In a state in which two arms of the hinge rotating member are overlapped with two arms of the hinge fixing member, the first rotary shaft members are coupled to connection portions provided at the overlapped arms, respectively. Thereby, the hinge rotating member can turn about a first rotation axis which passes through central portions of the first rotary shaft members. The second rotary shaft member is coupled to a central portion of the hinge rotating member. Thereby, the second rotary shaft member can turn about a second rotation axis which is orthogonal to the first rotation axis. This hinge apparatus needs not to be provided with a shaft core member extending axially.
In Japanese Patent Application Laid-Open No. 2000-240636, disclosed is a hinge apparatus provided with a pair of brackets, an opening/closing shaft and a rotary shaft. The opening/closing shaft is supported by the brackets at both end portions thereof. The rotary shaft rotatably passes through a central portion of the opening/closing shaft along a direction orthogonal to the opening/closing shaft. The opening/closing shaft and the rotary shaft respectively correspond to the first rotation axis and the second rotation axis which are disclosed in Japanese Patent Application Laid-Open No. 2001-272719.
In the image displaying apparatus, the first rotation axis in each of these hinge apparatuses is normally set to be a rotation axis for opening or closing an image displaying panel. Therefore, in respect of turning about the first rotation axis, the image displaying panel is required to be held in an arbitrary angular position. Furthermore, in respect of turning about the first rotation axis, it is required that a user can feel an appropriate and comfortable frictional feel and obtain a click feel at a specified angular position.
A hinge mechanism to meet the above-described requirements is disclosed in Japanese Patent Application Laid-Open No. H10 (1998)-311327. This hinge mechanism is provided with a shaft, a first cam, a second cam and a spring. The shaft extends along the first rotation axis. The first cam is operated together with the rotation of the shaft. The second cam is not operated together with the rotation of the shaft. The spring is inserted in the shaft to bias the second cam toward the first cam such that a cam face of the second cam is contacted with a cam face of the first cam. By this cam mechanism, the resistance against rotation can be obtained by a biasing force of the spring. Therefore, an image displaying panel is held at an arbitrary angular position and a click feel can be obtained at a specified angular position depending on a cam shape.
Meanwhile, an image displaying apparatus onto which the hinge apparatus as described above is mounted increasingly comes to be downsized and weight-saved accompanied with the enlargement of spread of mobile applications.
As the image displaying apparatus is downsized, the hinge apparatus is downsized and a plurality of members employed in the hinge apparatus are made thin for weight saving, which results in the tendency of decreased strength or rigidity. Normally, a predetermined rotation angle range in which an image displaying panel can be turned is set to the image displaying apparatus. Thus, in order to inhibit the image displaying panel from being turned over the predetermined rotation angle range, a stopper structure is provided at the hinge apparatus. However, due to thinning of the members employed in the hinge apparatus, the strength of the stopper structure tends to decrease.
Furthermore, even if, the members employed in the hinge apparatus are made thin, turning force to be applied to the image displaying panel by a user (force provided by hands) in order to position the image displaying panel in a desired posture, is not changed. Thus, when the image displaying panel is turned, force larger than the force to which the thinned stopper structure can be resistant is applied, which results in a higher possibility that the hinge apparatus is damaged.
In particular, in respect of turning about the first rotation axis, that is, opening or closing the image displaying panel, the image displaying panel is likely to bump on a wall or a desk in a state in which the image displaying panel is opened. When the image displaying panel is bumped on the wall or the desk, unintended force is forcibly applied to the stopper structure, which results in a high possibility that the hinge apparatus is damaged. Thus, even if the hinge apparatus is downsized, rotation-regulating strength of the stopper structure provided at the hinge apparatus is desired to keep high.
As described in Japanese Patent Application Laid-Open No. 2000-240636, a conventional rotation-regulating structure (stopper structure) is provided with an angle-regulating piece and an angle-regulating portion. The angle-regulating piece is formed at a bracket (opening/closing shaft support) by bending the bracket. The angle-regulating portion is provided at a plate preventing the opening/closing shaft from coming off, and extends outward from the periphery of the plate preventing the opening/closing shaft from coming off. By bringing the angle-regulating portion in contact with the angle-regulating piece of the bracket, an angle regulation of the opening/closing shaft is conducted.
In this rotation-regulating structure, the bracket is merely bent to form the angle-regulating piece. Thus, when strong force is applied to the angle-regulating piece, the angle-regulating piece is deformed to make it impossible to conduct a rotation regulation at a predetermined position and there is a possibility that a hinge apparatus is damaged.
The hinge apparatus described in Japanese Patent Application Laid-Open No. 2001-272719 is provided with a thin annular friction spring and a small hole, in order to hold an image displaying panel at an arbitrary angular position and obtain a click feel in a specified angular position. The friction spring is coupled to a connection portion provided at one arm of the hinge fixing member. The friction spring is engaged with the small hole to provide a click feel to a user. However, since the friction spring is formed to be annular, a sufficient stroke in a rotation axis direction cannot be obtained in an elastic deformation of the friction spring. Therefore, a problem exists in that frictional force is fluctuated or that a frictional touch of a high quality is hard to obtain. In addition, a further problem exists in that a click feel is hard to exhibit with a subtle frictional touch and that rotation operation of high quality is hard to obtain.
The hinge apparatus described in Japanese Patent Application Laid-Open No. 2000-240636 is provided with the pair of opening/closing shaft supports (brackets), a wavy spring and an opening/closing click plate, in order to hold an image displaying panel at an arbitrary angular position and obtain a click feel in a specified angular position. The opening/closing shaft supports are respectively provided at both ends of the opening/closing shaft to support the opening/closing shaft. The wavy spring is provided at one of the opening/closing shaft supports. The opening/closing click plate includes a spherical concavity to be engaged with a spherical protrusion formed at the wavy spring. However, since the wavy spring is formed in a thin annular shape, an elastic deformation region is narrow and, in the elastic deformation of the wavy spring, a sufficient stroke in a rotation axis direction cannot be obtained. Therefore, a problem exists in that frictional forces are fluctuated or that a frictional touch of high quality is hard to obtain. Furthermore, a further problem exists in that a click feel is hard to exhibit with a subtle frictional touch and that rotation operation of high quality is hard to obtain.
In a hinge mechanism described in Japanese Patent Application Laid-Open No. H10 (1998)-311327, since the cam faces of the first and the second cams can be set without restraint in a rotation axis direction and in an elastic deformation of the spring for biasing the second cam toward the first cam, a stroke in the rotation axis direction can be set to be large. Thus, a frictional force is stable and a frictional touch of high quality can be obtained. However, this hinge mechanism is provided with the shaft extending on the rotation axis and provided with the first cam, the second cam and the spring to be inserted in the shaft. Here, it is noted that the first cam and the second came are large in outer diameter. Therefore, if this hinge mechanism includes a mechanism of the rotation with a second rotation axis orthogonal to the first rotation axis, a problem exists in a larger hinge mechanism.